Terminal block



Oct. 21, 1969 J. P. MAHON ETAL 3,474,383

TERMINAL BLOCK Filed Oct. 16, 1967 INVENTORS JOSEPH PETER MAHON BOHDAN MISHKO BY KM ATTORNEY United States Patent *Ofitice Patented Oct. 21, 1969 US. Cl. 339-33 8 Claims ABSTRACT OF THE DISCLOSURE A terminal block including a plurality of like insulating sections with a pair of generally J-shaped bus bars retained between each two adjacent sections.

FIELD OF THE INVENTION BACKGROUND OF THE INVENTION Electric terminal blocks are used, generally speaking, to interconnect electric conductors and are frequently used to interconnect two or more electric components which have been separately assembled and wired. Terminal blocks for these and other purposes have been used for many years and are available in many different shapes and sizes. Nevertheless, when the present inventors needed a terminal block for a particular application, they were unable to obtain a satisfactory model from commercial sources and therefore set about developing one which would be satisfactory. In the course of this development the present invention was made.

It is a general object of the present invention to provide an improved terminal block.

Another object is to provide a sectional terminal block which can be assembled easily in various sizes as required.

Another object is to provide a terminal block in which the electric connections thereto can be made quickly and easily.

Another object is to provide a terminal block which conserves lengthwise space.

Another object is to provide a terminal block in which the possibility for inadvertent loosening of the connections is minimized.

Another object is to provide a terminal block with provision for readily attaching and releasing temporary test leads.

Another object is to provied a terminal block to which a marker strip may be applied readily.

Another object is to provide a terminal block to which conductors without lugs or eyelets can be readily fastened.

SUMMARY OF THE INVENTION One specific example of a terminal block incorporating the invention is a sectional block which can be assembled quickly to any reasonable length desired from a stock of a few basic parts. The principal parts are first, a generally flat insulating section formed with various protuberances and recesses on each side and second, a bus bar assembly comprising a flat, generally J-shaped conductive strip with a machine screw threaded into each leg of the J near its end. Each screw is provided with a slightly arched, captive, resilient, metal washer formed with a small upstanding lug and with corrugations on its under side. Two such bus bar assemblies are positioned between each two adjacent insulating sections where they are retained by the aforesaid protuberances and recesses. The bottom of each insulating section is formed into a dovetail so that the sections, as assembled, can be slipped between the flanges of a standard mounting base to which they may be clamped.

BRIEF DESCRIPTION OF THE DRAWING For a clearer understanding of the invention, reference may be made to the following detailed description and its accompanying drawing, the single figure of which is an exploded view of a terminal block incorporating the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, there are shown a plurality of identical upstanding insulating sections 11 which may, for example, be made of a phenolic resin. Each section has a thin central portion 12, on the first face of which are formed three laterally extending protuberances" 13, 14 and 15. The latter two are located symmetrically on either side of the vertical centerline of the portion 12 and are mirror images of each other while the former is symmetrical about the vertical centerline. The protuberance 13 is formed at the bottom with a flaring tenon or dovetail 16 which is intended to cooperate with a mating base (not shown).

Above the dovetail 16, the protuberance 13 is formed on each side to define two coplanar horizontal ledges 17 and 18 separated by a recess 19. Bounding the outside of the ledge 17 is an upstanding shoulder 21. Just below the edge 17 and the shoulder 21, the protuberance 13 has a cylindrical aperture 22 formed therein. A centrally located stem 23 extends upward, terminating in a generally triangular cap 24 having a sloping surface 25 on each side. The stem 23 has an elongated vertical recess or slot 26 formed therein.

The protuberance 14 is located just above the ledge 18 and includes a lower horizontal surface spaced therefrom and which defines, with the ledge 18, a generally horizontal slot or recess 31. The protuberance 14 also includes a generally vertical surface spaced from the stem 23 which defines therewith a vertical slot or recess 32. Extending upward and toward the outside from the main portion of the protuberance 14 is a stem portion 33 terminating in a small horizontal ledge 34.

As previously mentioned, the protuberance 15 is a mirror image of the protuberance 14 and therefore need not be further described.

The second face of the section 11 is similar, in fact almost identical, to that just described. The protuberances 13, 14 and 15, in effect, extend through the central portion 12 to the other side to a position directly opposite and are identical except that instead of the cylindrical recess 22 and its mirror image recess 36, the second side has formed thereon complementary cylindrical extending portions or pins 37 and 38 and instead of the elongated recess or slot 26 there is a complementary extending portion or vane 39.

A plurality of identical bus bar assemblies are indicated generally by the reference character 41. Each comprises a flat strip of conductive material such as brass formed in the general shape of the letter I so as to have a short leg 42 and a long leg 43 substantially parallel to each other and joined by a connecting portion 44. Each of the legs 42 and 43 is formed with a threaded aperture 45 to receive a machine screw 46. Each screw 46 is provided with a captive washer 47 free to rotate on the shank but retained longitudinally to a position adjacent the head. The washer 47 is made of a resilient, conductive material such as spring steel and is generally, but not quite, rectangular, being slightly arcuate, or bowed, as shown. Each washer 47 is formed with a small upstanding lug 48 at one end to which a test lead may be clipped. The bottom of each washer is formed with a row of corrugations 49 on each side of the screw 46. The top of each of the legs 42 and 43 is formed with similar rows of corrugations 51 on each side of its threaded aperture.

To assemble a terminal block, a bus bar assembly 41 is placed, for example, on the left side of the first face of an insulating section 11 with the connecting portion 44 in the recess 32 adjacent the stem 23, the leg 42 resting on the ledge 34 and the leg 43 resting on the ledges 17 and 18 adjacent to the shoulder 21. A second bus bar assembly 41 may now be similarly placed on the right side of the same face of the same section 11 with the two connecting portions 44 back to back and spaced apart by the central stem 23. When so placed the two short legs 42 are substantially coplanar and extend away from each other, in opposite directions from each other and from the stem 23. Similarly, the two long legs 43 are substantially coplanar and extend in opposite directions.

It is to be noted that the shank of the screw 46 of the long leg 43 extends into the recess 19 while the shank of the screw 46 of the short leg 42 extends into the space between the stem 33 of the protuberance 14 and the stem 23 of the protuberance 13. It is also to be noted that the ledges 17, 18 and 34 are approximately one half, or slightly less, of the width of the legs 42 and 43.

Next a second insulating section 11 is placed with its second face toward the first face of the above section. As the two sections are brought together, a pair of cavities are formed therebetween, the respective protuberances 13, 14 and 15 abut each other, the corresponding recesses 19, 31 and 32 are opposite each other, the pairs of ledges 17, 18 and 34 jointly support the bus bar assemblies 41, the extending portions or pins 37 and 38 enter the cylindrical recesses 22 and 36, and the vane 39 enters the elongated recess 26. Thus the two bus bar assemblies are held securely by the two insulating sections.

As many additional terminals as desired can be provided by using one additional insulating section for each additional pair of bus bar assemblies. It is contemplated that the dovetail of each section will he slipped under the flanges of a suitable base as the assembly proceeds and that the completed unit will be held by suitable clamps. The base and the clamps have not been illustrated since they are well known and form no part of the present invention.

Conductors may be attached very easily. No lugs or eyelets are required. The installer strips the insulation from the end of the wire and, while holding it with one hand, uses a screw driver with the other to loosen the screw 46 on the long leg 43. As the screw is loosened, the captive washer 47 is prevented from rotating by its engagement with the central portion 12 of each section 11. The washer rises, forming a space between the leg 43 and the washer 47 into which the end of the conductor is inserted, whereupon the screw 46 is tightened. The corrugations 49 and 51 grip the conductor and the armate washer 47 is flexed thereby exerting a force against the head of the screw so as to keep it tight. Next a second conductor can be positioned over the first and fastened to the short leg 42.

It is to be noted that for each pair of conductors, two lugs 48 are available which are useful for the temporary connection of test leads by means of prods, alligator clips or the like.

It is also to be noted that as the sections 11 are joined, the surfaces 25 on each side of each section abut and are coplanar with those of adjoining sections so that two substantially planar elongated surfaces are formed at the top of the unit. These surfaces are for the application of a marker strip, such as a strip of gummed paper or tape, to which indicia can be applied to identify the various terminals.

It is also to be noted that both conductors of a pair to be connected together extend to the same side of the terminal block rather than to opposite sides as is more usual. Additionally the conductors are positioned one above the other. Also, two pairs of conductors, one pair on each side, can be accommodated in the lengthwise space normally used by a single pair. Thus there is a saving in lengthwise space, which is often at a premium, at the price of vertical space, of which more is usually available.

The terminal block has been described as one in which the J-shaped bus bars are oriented with the J lying on its side, with the connecting portions back to back, and the legs horizontal. There is no fundamental reason why the bus bars could not be positioned with the long legs back to back and arranged with each I either upright or upside down. However, such an arrangement would require a redesign of the insulating sections and the configuration illustrated and described is preferred at present.

Throughout the specification reference has been made to the bottom or the top etc. because it is contemplated that the terminal block will be mounted with the dovetail on the bottom and resting on a horizontal surface. However, there is no reason why the terminal block cannot be installed on an inclined surface or on a vertical surface, or, for that matter, upside down on the ceiling. Therefore, the terms up, down and the like are to be understood to be used in an illustrative rather than a limiting sense.

Although a preferred embodiment of the invention has been described in considerable detail for illustrative purpurposes, many modifications within the spirit of the invention will occur to those skilled in the art. It is therefore desired that the invention not be limited to the particular embodiment which has been described.

What is claimed is:

1. A sectional terminal block, comprising, a plurality of bus bars, each of said bus bars comprising a generally fiat conductive strip formed in the general shape of the letter I so as to include a long leg, a short leg substantially parallel thereto, and a connecting portion, said bus bars being arranged in pairs with the connecting portions adjacent to but insulated from each other and with corresponding legs of the two bars substantially coplanar and extending in opposite directions, away from each other, each leg of each bus bar being provided with means for connecting an external conductor thereto, and a plurality of upstanding insulating sections, each section having a support portion and each having a generally flat central portion and each formed with a plurality of laterally extending protuberances on each face opposite each other, said sections being arranged side by side with a pair of said bus bars arranged as aforesaid between each two adjacent sections, said central portions being arranged to extend between adjacent conductor connecting means, said protuberances on each face being shaped and located so that corresponding portions on adjacent sections abut each other and form a pair of spaced cavities to retain said bus bars in position therein, each said pair of cavities being arranged to open outwardly in opposite directions, each said cavity also being arranged to open upwardly, said protuberances on each face including a first protuberance extending between said pair of adjacent bus bars, said first protuberance also extending between said adjacent support portion and each said bus bar.

2. A terminal block according to claim 1 in which said support portions on said sections are dovetail portions projecting therefrom, said dovetail portions being aligned in order to fit between the flanges of a standard mounting base, and in which said first protuberance on each face has a first stern portion and a second main portion and has a generally T-shaped profile, said stem portion extending between said pair of bus bars adjacent thereto, said second portion extending between each said bus bar and said dovetail portion adjacent thereto, and in which said protuberances on each face include second and third protuberances respective disposed on opposite sides of said stem portion and forming a pair of generally L shaped slots therebetween receiving said pair of bus bars.

3. A terminal block according to claim 2 in which said second portion of the first protuberance on each face has a pair of shoulder portions disposed at opposite ends thereof for supporting the oppositely disposed ends of the long legs of said pair of adjacent bus bars, each said shoulder portion having a recess adjacent thereto for receiving a conductor connecting screw, and in which said second and third protuberances have respective stem portions for supporting the oppositely disposed ends of the short legs of said pair of adjacent bus bars, each said stem portion having a recess adjacent thereto for receiving a conductor connecting screw.

4. A terminal block according to claim 3 in which each section is formed on one face with an elongate vane portion extending from and formed on the stem portion thereof, and each section is formed on the other face with an elongate portion complementary to said -vane portion whereby upon assembly said vane portion of one section engages said complementary portion of the adjacent section.

5. A terminal block according to claim 4 in which each of said means for connecting comprises a machine screw threaded into a leg of said bar and disposed between said pair of central portions adjacent thereto, said machine screw being provided with a conductive washer held captive near the head thereof, said washer being generally rectangular in shape and arranged to engage said central portions adjacent thereto, and said washer being formed of a resilient metal in a slightly arcuate profile for ease of connecting a conductor to said leg, and in which said Washer is formed with an upstanding lug to facilitate the temporary connection of a test lead thereto.

6. A sectional terminal block, comprising, a plurality of bus bars, each of said bus bars comprising a generally fiat conductive strip formed in the general shape of the letter J so as to include a long leg, a short leg substantially parallel thereto, and a connecting portion, said bus bars being arranged in pairs with the connecting portions adjacent to but insulated from each other and with corresponding legs of the two bars substantially coplanar and extending in opposite directions, away from each other, each leg of each bus bar being provided with means for connecting an external conductor thereto, and a plurality of upstanding insulating sections each having a generally flat central portion and each formed with a plurality of laterally extending protuberances on each face opposite each other, said sections being arranged side by side with a pair of said bus bars arranged as aforesaid between each two adjacent sections, said protuberances being shaped and located so that corresponding portions on adjacent sections abut each other and retain said bus bars in position, each section also being formed on one face with at least one extending portion formed on and extending beyond said protuberances and formed on the other face with at least one recess in said protuberances complementary to said extending portion, whereby upon assembly said extending portion of one section fits into said recess of the adjacent section, and in which each of said means for connecting comprises a machine screw threaded into a leg of said bar and provided with a conductive washer held captive near the head thereof, said washer being generally rectangular in shape and being formed of a resilient metal in a slightly arcuate profile, and in which each leg of said bus bar and each washer is formed with corrugations on facing surfaces to enhance their engagement with an external conductor.

7. A terminal block according to claim 6 in which each of said insulating sections is formed with two planar surfaces each of which is so located thereon as to be coplanar and contiguous with a like surface on an adjacent section when said sections are assembled and which surfaces form areas suitable for the application thereto of marker strips bearing indicia.

8. A terminal block according to claim 7 in which each of said bus bars is positioned with its two legs in different generally horizontal planes with the long leg lowermost, the connecting portion upstanding, and the short leg uppermost.

References Cited UNITED STATES PATENTS 2,787,773 4/1957 Potter 339l98 2,922,139 1/1960 Ustin 339198 3,050,706 8/1962 Kitscha 339246 3,178,675 4/1965 Gutshall 339246 FOREIGN PATENTS 1,292,367 3/1962 France.

829,683 3/ 1960 Great Britain.

RICHARD E. MOORE, Primary Examiner U.S. Cl. X.R. 

